The present invention relates to a semiconductor device having a Hall-effect element or elements for current detection.
Integrated semiconductor circuits have been known in which a Hall-effect element or elements, built on the proportionality of the Hall voltage of a semiconductor to the applied magnetic field, and an amplifier or amplifiers for the Hall-effect element or elements are formed on a unitary semiconductor substrate.
Conventionally, however, the integrated circuits including Hall-effect elements have been used solely for detection of external magnetic fields (those applied from without the integrated circuits) and not for detection of input and output currents of other semiconductor elements within the integrated semiconductor circuits. Additionally, the prior art integrated circuits have not possess sufficient sensitivity to detect currents of relatively small magnitude flowing inside the circuits. Also, the integrated circuits including Hall-effect elements have not been constructed to be free from the influence of undesired external magnetic fields.
It is therefore an object of this invention to provide a semiconductor device capable of accurately and easily detecting the currents of electric circuits by a Hall-effect element.
The current-detecting semiconductor device according to the present invention comprises a semiconductor substrate having a Hall-effect element, an insulating film disposed on a surface of the semiconductor substrate, and a conductor layer disposed on the insulating film so as to extend along the Hall-effect element as seen in a planar view and so formed as to permit an electric current of an electric circuit to flow therein.
Thus the conductor layer for carrying a current to be detected can be disposed close to the Hall-effect element. As a result, the current can be accurately detected by the Hall-effect element. Also, the positional relationship between the Hall-effect element and the conductor layer can be accurately and easily determined, resulting in the reduction of fluctuations of the values detected.
Desirably, the conductor layer should be so formed as to surround the Hall-effect element in order to augment the amount of magnetic flux applied to the Hall-effect element.
It is also desirable to provide a first and a second Hall-effect element and to arrange the conductor layer so that magnetic fields may be applied to the first and the second Hall-effect element in opposite directions, for enhancement of current-detecting sensitivity and suppression of noise.
It is also desirable to provide a Hall-effect element or elements and another circuit element on the same semiconductor substrate for the provision of a compact and inexpensive semiconductor device having a Hall-effect element.
It is also desirable to provide a magnetic collector in order to cause the magnetic flux that has been produced by the current carried by the conductor layer, to work effectively on the Hall-effect element.